import sys
def check_password(password):
    if len(password) <= 8:
        return "NG"

    bool_s = [False]*4
    for char in password:
        if char.isdigit():
            bool_s[0] = True
        elif char.islower():
            bool_s[1] = True
        elif char.isupper():
            bool_s[2] = True
        else:
            bool_s[3] = True
        
    if sum(bool_s) < 3:
        return "NG"

    for i in range(len(password) - 2):
        char = password[i:i+3]
        if password.find(char,i+1) != -1:
            return "NG"
    return "OK"

input_data  = sys.stdin.read().strip().splitlines()
results = [check_password(password) for password in input_data]
for result in results:
    print(result)